1. Field of the Invention
The present invention relates to a lamp and an illumination system. More particularly, the present invention relates to a light emitting diode (LED) lamp and an illumination system using the LED light source.
2. Description of Related Art
LEDs are semiconductor devices. The light emitting chips are mainly made of a compound semiconductor material containing III-V group chemical elements, for example, GaP, GaAs, and the like, and function on the principle of converting electric energy to light. That is to say, the compound semiconductor is powered to release excessive energy through the combination of electrons and holes, so as to emit photon (light). The LED can emit light without being heated or does not discharge to emit light. Therefore, the lifespan of the LED is up to 100,000 hours, and an idling time is not required. In addition, the LED has advantages of quick response speed (approximately 10−9 seconds), small volume, power-saving, low pollution, high reliability, and ease mass production. Thus, the LEDs have been intensively used in many fields, for example, light source and illumination device in large-scale bulletin boards, traffic lights, cellular phones, scanners, fax machines, etc.
The light emitting brightness and efficiency of the LEDs are continuously improved, and meanwhile the white LEDs are successfully put into mass production, so the LED have been gradually used for illumination purpose, and LED bulbs have been developed. However, mostly the LED bulbs may provide constant brightness. If the brightness is required to be adjusted, usually a current control circuit capable of modulating current is installed in a power distribution system so as to control the LED bulbs to vary in brightness. However, if the power distribution system in the environment of the user does not have the current control circuit capable of modulating current, the LED bulbs cannot change brightness according to requirements of the user. In other words, currently, the application of the LED bulbs is limited.